Path: chuka.playstation.co.uk!news From: Steve Parnell Newsgroups: scee.yaroze.programming.3d_graphics Subject: Re: What is a normal? Date: Fri, 14 Aug 1998 10:25:58 +0100 Organization: Architectronics Lines: 21 Message-ID: <35D402A6.8830674@parny.force9.co.uk> References: <35D3F965.D5D79825@nospam.easynet.co.uk> Reply-To: steve@parny.force9.co.uk NNTP-Posting-Host: 74.usr01.shef.dialup.force9.net Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Mailer: Mozilla 4.04 [en] (WinNT; I) > > I keep hearing people talking about 'normals' in relation to polygons/3D > stuff. > > Could someone explain to me what a normal is? > > I know what a vertice and a polygon is, and I understand about matrices > and vectors, if that helps! > > Phil A normal is simply a vector which is perpendicular to a plane. If you have 2 vectors describing a plane, its normal will be 90 degrees to both these vectors. For example, the normal to a flat screen (say LCD monitor) is the vector emanating directly outwards from it. Hope this helps and doesn't confuse you more! Steve P.